Number of -n..n arrays x(0..3) of 4 elements with zero sum and no two consecutive zero elements.

Terms

a(0) =12a(1) =72a(2) =212a(3) =464a(4) =860a(5) =1432a(6) =2212a(7) =3232a(8) =4524a(9) =6120a(10) =8052a(11) =10352a(12) =13052a(13) =16184a(14) =19780a(15) =23872a(16) =28492a(17) =33672a(18) =39444a(19) =45840a(20) =52892a(21) =60632a(22) =69092a(23) =78304a(24) =88300a(25) =99112a(26) =110772a(27) =123312a(28) =136764a(29) =151160